An information processing system including a plurality of power supply units is short of power and therefore may be down if only one power supply unit is in a faulty state, when the information processing system is operated by N (N is an integer of 2 or more) power supply units that are required in terms of a design of the system. Therefore, in the related art, in order to avoid the system down, there is a case in which the power supply unit is operated in an N+1 redundant configuration.
Further, in the information processing system including the N power supply units, a technique has known that the system saves power using a fault signal of the faulty power supply unit, in order to continue to operate the system, even when one power supply unit is faulty (see, for example, Patent Literature 1 or 2).
FIG. 6 is a diagram for describing an example of power supply control processing in an information processing system 100. As illustrated in FIG. 6, the information processing system 100 includes plural, for example, two power supply units 200-1 and 200-2 (hereinafter, simply referred to as power supply unit 200 when there is no need to differentiate the power supply units 200-1 and 200-2) and a load unit 300.
Each power supply unit 200 includes a voltage conversion circuit 210, an output capacitor 220, a fault signal sending circuit 240, and an abnormal detection circuit 241.
The voltage conversion circuit 210 converts input voltage of AC 200 V from AC (L) and AC (N) into predetermined output voltage (DC voltage of DC+12 V) and supplies power to the load unit 300 via power lines 110 and 120. The output capacitor 220 stabilizes and outputs the output voltage converted by the voltage conversion circuit 210. The abnormal detection circuit 241 detects the abnormality (for example, the abnormality of the output voltage or the abnormality of temperature) of the power supply unit 200. The fault signal sending circuit 240 sends the fault signal to the load unit 300, and the like, via a control line 130-1, 130-2, 140-1 or 140-2 when the abnormality of the power supply unit 200 is detected by the abnormal detection circuit 241.
The load unit 300 is operated using power supplied from the power supply unit 200 and includes a power reduction signal sending circuit 310 and a processing unit 320 including a central processing unit (CPU), a memory, an input output (IO) device, and the like. When receiving the fault signal from the power supply unit 200, the power reduction signal sending circuit 310 instructs the processing unit 320 via a control line 150 to reduce power consumption. When receiving the power reduction instruction, the processing unit 320 performs power saving.
Hereinafter, a detailed example will be described with reference to FIG. 6. As an example, when the load of the system is maximum, the load current of the system (load unit 300) is 140 A and when the power supply units 200-1 and 200-2 are normally operated, the power supply units 200-1 and 200-2 each output the output current of 70 A.
In FIG. 6, for example, when the power supply unit 200-2 is faulty, the output current of the power supply unit 200-2 is changed from 70 A to 0 A (see (i) in FIG. 6) and the power supply unit 200-2 sends the fault signal to the load unit 300 (see (ii) in FIG. 6). The power reduction signal sending circuit 310 of the load unit 300 receives the fault signal from the power supply unit 200-2 and instructs the processing unit 320 to reduce power (see (iii) in FIG. 6). The processing unit 320 receives the power reduction instruction to reduce, for example, an operating frequency (see (iv) in FIG. 6) and suppresses the load current of the system to the supply current 70 A of the power supply unit 200-1 (see (v) in FIG. 6). Therefore, even when the power supply unit 200-2 is faulty, the system may be operated with the supply current 70 A of the power supply unit 200-1, such that the system may not be short of power and may be continuously operated. Further, the output current of the power supply unit 200-1 is increased from 70 A to 140 A, but the load current of the load unit 300 is reduced to 70 A, according to the fault of the power supply unit 200-2, such that the power supply unit 200-1 may continuously output 70 A (see (vi) in FIG. 6).
[Patent Literature 1] Japanese Laid-open Patent Publication No. 11-338555
[Patent Literature 2] Japanese Laid-open Patent Publication No. 11-18295
[Patent Literature 3] Japanese Laid-Open Patent Publication No. 2001-352750
[Patent Literature 4] Japanese Laid-Open Patent Publication No. 5-181430
As described above, the information processing system in which the power supply unit has an N+1 redundant configuration includes a power supply unit of required numbers (N numbers) or more, which leads to an increase in cost.
Further, in the example illustrated in FIG. 6, the information processing system 100 including two (N) power supply units uses the fault signal from the power supply unit 200 so as to allow the load unit 300 to uniformly perform the power saving. For this reason, even in the state in which the system may be operated with the supply power of one (N−1) power supply unit, such as the state in which the number of empty slots of the IO is increased and thus the load power of the system is extremely small, and the like, when the fault of one power supply unit 200-2 is detected by the system, the processing unit 320 carries out the unnecessary power saving. In addition, since the power saving is continued until the faulty power supply unit 200-2 is exchanged with the normal power supply unit 200, the performance of the system is continuously reduced.